I've never had a problem with ECA reducing the effectiveness of birth control. But, that's not backed up by any medical documentation. I can't find any online documentation which addresses whether ephedrine does or does not interfere with birth control effectiveness.

I have been taken ECA stacks and birth control for years. I asked my doctor if I should take any extra precautions and at the time he told me that St. John's Wort was the only herbal supplement that was proven to decrease the effects of birth control at that time.

my girlfriend is also on birth control, and also doesnt have the best kidneys(some kind of kidney disease that runs in her family, cant think of the name right now). she is trying to find a good supplement to give her a little more energy and help burn a little fat. i have been trying to find something that would be good for her but i dont take any stimulants or fat burners so i really dont know what the best is from my experience and especially one that is good for a girl. so any information would be very helpful. thanks